The disclosure relates generally to high-silica content substrate materials, and specifically to high-silica content substrate materials for deposition of reactive materials and/or for use in high temperature material deposition environments, such as thin-film battery material deposition. Silica soot may be generated by a process, such as flame hydrolysis. The silica soot may then be sintered to form a fully or partially sintered high silica content substrate. Thin-film batteries, such as thin-film rechargeable lithium batteries, contain thin-film layers of cathode material, anode material, separator material, electrolyte material and current collector material.